Hydrogensulfide(H2S) hasemergedasacriticalmediatorofmultiplephysiologicalprocessesin
mammaliansystems.Thepathwaysinvolvedintheproduction,consumption,andmechanismofaction
of H2S appeartobesensitivetoalterationsinthecellularredoxstateandO2 tension.Indeed,the
catabolismofH2S throughaputativeoxidationpathway,thesulfidequinoneoxido-reductasesystem,
is highlydependentonO2 tension. DysregulationofH2S homeostasishasalsobeenimplicatedin
numerouspathologicalconditionsanddiseases.Inthisreview,thechemistryandthemainphysiolo-
gical actionsofH2S arepresented.SomeexampleshighlightingthecytoprotectiveactionsofH2S within
the contextofcardiovasculardiseasearealsoreported.ElucidationoftheredoxbiologyofH2S will
enable thedevelopmentofnewpharmacologicalagentsbasedonthisintriguingnewredoxcellular
signal.